Harry recently purchased a new store-brand laundry detergent and was impressed by the product. He has decided that he is going to buy another box of the same detergent as soon as he runs out of the one he's using. In the context of operant conditioning, this is an example of the nature of: Select one:
a. cognitive approval obtained from former actions.
b. cognitive dissonance obtained from former actions.
c. physiological response obtained from former actions.
d. retrieval obtained from former actions.
e. reinforcement obtained from former actions.